Change Process.start to return a future that completes with a

utils/testrunner/pipeline_utils.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of pipeline;
 
 List stdout, stderr, log;
 var replyPort;
 int _procId = 1;
 Map _procs = {};
@@ skipping 42 matching lines @@
  * If [procId] is non-zero (i.e. called from startProcess) then a reference
  * to the [Process] will be put in a map with key [procId]; in this case
  * the process can be terminated later by calling [stopProcess] and
  * passing in the [procId].
  * [outputMonitor] is an optional function that will be called back with each
  * line of output from the process.
  * Returns a [Future] for when the process terminates.
  */
 Future _processHelper(String command, List<String> args,
     [int timeout = 300, int procId = 0, Function outputMonitor]) {
-  var completer = new Completer();
+  var completer = procId == 0 ? new Completer() : null;
   log.add('Running $command ${Strings.join(args, " ")}');
   var timer = null;
   var stdoutHandler, stderrHandler;
-  var process = Process.start(command, args);
-  if (procId != 0) {
+  var processFuture = Process.start(command, args);
+  processFuture.then((process) {
     _procs[procId] = process;
-  }
-  process.onStart = () {
+
     timer = new Timer(1000 * timeout, (t) {
       timer = null;
       process.kill();
     });
-  };
-  process.onExit = (exitCode) {
-    if (timer != null) {
-      timer.cancel();
-    }
-    process.close();
-    if (completer != null) {
-      completer.complete(exitCode);
-    }
-  };
-  process.onError = (e) {
+
+    process.onExit = (exitCode) {
+      if (timer != null) {
+        timer.cancel();
+      }
+      process.close();
+      if (completer != null) {
+        completer.complete(exitCode);
+      }
+    };
+
+    _pipeStream(process.stdout, stdout, outputMonitor);
+    _pipeStream(process.stderr, stderr, outputMonitor);
+  });
+  processFuture.handleException((e) {
     stderr.add("Error starting process:");
     stderr.add("  Command: $command");
     stderr.add("  Error: $e");
     completePipeline(-1);
-  };
-
-  _pipeStream(process.stdout, stdout, outputMonitor);
-  _pipeStream(process.stderr, stderr, outputMonitor);
+    return true;
+  });
 
   return completer.future;
 }
 
 void _pipeStream(InputStream stream, List<String> destination,
                  Function outputMonitor) {
   var source = new StringInputStream(stream);
   source.onLine = () {
     if (source.available() == 0) return;
     var line = source.readLine();
@@ skipping 73 matching lines @@
   stderr = new List();
   log = new List();
 }
 
 void completePipeline([exitCode = 0]) {
   replyPort.send([stdout, stderr, log, exitCode]);
 }
 
 /** Utility function to log diagnostic messages. */
 void logMessage(msg) => log.add(msg);